1. Field of the Invention
The present invention relates to a compound torque hinge suitable for use for opening and closing an opening-closing body especially of a Western style toilet.
2. Description of the Related Art
As an opening-closing hinge of Western style toilet seat and seat cover, there have been known such hinges as a hinge which is used in a cam mechanism with a compression spring on a rotating shaft, a hinge which uses a torsion spring acting in a direction in which a torque in a specific direction of rotation of the rotating shaft is cancelled, and a hinge using a fluid damper acting on the rotating shaft.
The prior art hinge used in the cam mechanism provided with the compression spring on the rotating shaft has the advantage that a torque produced is easily adjustable to the turning moment of the toilet seat and seat cover. Despite of this advantage, however, the hinge has such a drawback that the use of a large-sized device is needed to obtain a great torque.
Also, the hinge using only the prior art torsion spring on the rotating shaft has the advantage that even a small-sized device can produce a great torque. However, the hinge producing a linearly increasing or decreasing torque is not adjustable to the turning moment of the toilet seat and seat cover that draws a sine curve. The device, therefore, has such a drawback that it is hard to make adjustments of details with respect to the turning moment of the seat and seat cover and also to accentuate operation.
Furthermore, a hinge using only a prior art fluid damper has the drawback that it is hard to make fine adjustment or accentuation in opening and closing the toilet seat and seat cover, and particularly for example to provide a function to stop and hold the toilet seat at an intermediate angle or to apply a brake to the toilet seat from a predetermined angle of opening.